Automatic adjusting air-escape valve for railway-brakes.



S. CHENEY. AUTOMATIC ADJUSTING AIR ESCAPE VALVE FOR RAILWAY BRAKES.

SAMUEL CHENEY, OF WICKEPIN, WESTERN AUSTRALIA, AUSTRALIA.

AUTOMATIC ADJUSTING AIR-ESCAPE VALVE FOR RAILWAY-BRAKES.

Listare.

Specification of Letters Patent.

Patented Apr. 2?, i9i5.

Application led November 23, 1914. Serial No. 873,577.

T0 zZZ whom t may concern:

Be it known that I, SAMUEL CHENEY, a subject of the King of GreatBritain, and residing at Wickepin, Western Australia, Commonwealth ofAustralia, have invented certain new and useful Improvements inAutomatic Adjusting Air-Escape Valves for Railway-Brakes, of which thefollowing is a specification.

This invention has been devised to provide an automatically workingappliance to be used in open communication with that portion of thepneumatic brake system known as the train pipe the object of theinvention being that in case of emergency a sudden freeing of the airpressure may be accomplished so that the brakes may be quickly applied.

In order that my invention may be clearly understood the same will beexplained with the aid of the attached drawing wherein the figurerepresents the invention in sectional elevation.

In apparatus embodying my invention which may be modified to suitvarying working conditions of the train brake gear I employ a dependingopen cylinder as z the neck b of which interscrews with a T piece of thetrain air pipe. rIhe lower part of this cylinder a is internally screwthreaded as at 0 so as of a sleeve cylinder Z thus forming two cylindersas a and Z the cylinder Z being open mouthed at its top end thuscommunieating with the upper and larger cylinder as L and providing aresultant and annular space as e between said cylinders.

In the interior cylinder Z are a number of air inlet holes f placedradially and giving free access with the said annular space e as shown.The cylinder cZ suitably connects by screw thread with the cylinder gwhich latter is of a lesser internal bore than that of the cylinder Zthus resulting in dierential areas for the respective pistons Z1 and g1.

The cylinder g is formed with radially arranged air exit holes y'opening to the atmosphere, said cylinder g at its bottom having athreaded neck lo whereby connection is made with the air reservoir 101.In the smaller cylinder g is a piston g1 carried on the bottom end ofthe tubular piston rod lg2 and said rod at its upper end carries thepiston Z1 working in its cylinder d. The bore of the tubular piston rodg2 at its upper end is restricted to a suitable degree by a tointerscrew with the bottom' small removable screw cap Z2 having acontracted orifice for the admission of air into the reservoir k1.

This invention makes provision whereby upon a suflicient release of airpressure in the train pipe the compound tandem pistons Z1 and g1 willmove upward thus causing piston Z1 to uncover the air inlet ports f asshown by broken lines and so allowing air to escape therethrough andunderneath piston Z1 and thence into the cylinder g and so by way of theexit ports 7' into the outer atmosphere. The object of the contractedneck Z2 in the top of the tubular piston rod is to provide a retardationof the air exhaust from the reservoir cl when a rapid reduction of airpressure takes place in the train pipe. This retardation of air exhaustallows a superior pressure to be exerted on the bottom face of thepiston g1 and consequently causes the upward movement of both pistonsand as soon as the air in the train pipe and reservoir has been fullyexhausted the pistons will fall by gravity to the position as seeny infull lines in the drawing. When the train pipe is again charged the airwill flow into the reservoir k1 through the contracted neck Z2 andtubular piston rod. The orifice in said neck Z2 is of an approved areato exhaust the air from the reservoir within suit the proper workingrequirements of the train brake gear as a whole. I may employ a spiralspring and interpose it between the piston Z1 and the underside of theneck o of cylinder a so that its expansive function may operate to pressdown said piston and assist in its fall by gravity when the air hasfully escaped from reservoir k1 while on the upward stroke of the pistonthe spring prevents it from leaving its cylinder d.

What I claim as my invention and desire to secure by Letters Patentis 1. In air brake apparatus, an automatically acting air escape valvecomprising a casing having a pair of cylinders of different diameters,the larger cylinder adapted to be connected to the train pipe and thesmaller cylinder to an air reservoir, pistons working in said cylinders,and a tubular rod connecting the pistons and providing means forconducting air between the operative faces of the pistons, air ventsbeing formed in the casing between said pistons, and the larger cylinderhaving ports in its wall ara given time limit and to ranged to beuncovered piston to admit the flow to said vents.

2. In airy brake apparatus, an automatically acting air escape valvecomprising a by the respective pair of cylinders of different-diameters,the'k larger cylinder opening and closing the ports l therein in itsmovements, and a tubular rod connecting sald pistons'ln tandem andserving to feed air between thevtrain pipe. and

said reservoir.

3. In air'brake apparatus, the-combination of a pair of cylinders ofdifferent diamtrain pipeY K sion ports therein, v

said `pistons mtandem and providing air eters, the'cylinder of largerdiameter having one. end/in communication With,I thetrainv pipe and alsohaving ports in its side Wall to'admit air thereto from the train pipe,Yand the smaller cylinder having one end in :communication with an airreservoir andhaving air vent ports in its side Wall, pistons Working' insaid cylinders, the piston in the larger cylinder controlling said airadminisand means connecting communication betWeenthe operative faces ofthe pistons. L

In testimony whereof I have hereunto set my. handin presence .oftwo-subscribing Witnesses.

SAMUEL CHENEY. Witnesses: f

RICHARD SrRRom SAMU-EL RINTEL.

, Copies of thisv patent may be obtained for five" cents each, by-addressing the'f Conimissio'nenof Patents Washington, D. C. Y

